You can probably use either Add Grid Values to Points or Grid Values to Points tool. They are under "Shapes- Grid" of Tools manager. (see below image, from SAGA 2.1.2)
If you already have a Point Shapefile which represents your points of interest (from where you want to extract the cell value), please use 'Add Grid Values to Points' tool.
If not, 'Grid Values to Points' will create a new Shapefile for you with an attribute column named after the raster filename, in which the extracted cell-values. You would prefer to choose Type: nodes, which produces point Shapefile, every cell is represented by a point - "node". (Type: cells will give you something grid-like.)